Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1YuLvN-0006OT-TK for pgsql-admin@arkaria.postgresql.org; Mon, 18 May 2015 14:21:46 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1YuLvM-0007Zh-DA for pgsql-admin@arkaria.postgresql.org; Mon, 18 May 2015 14:21:44 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1YuLvC-0007K0-Im for pgsql-admin@postgresql.org; Mon, 18 May 2015 14:21:34 +0000 Received: from mail4.neteven.com ([5.135.111.119]) by makus.postgresql.org with esmtp (Exim 4.84) (envelope-from ) id 1YuLv5-0007Yr-MD for pgsql-admin@postgresql.org; Mon, 18 May 2015 14:21:32 +0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by mail4.neteven.com (Postfix) with ESMTP id 06CB31F0169; Mon, 18 May 2015 16:21:27 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at mail4.neteven.com Received: from mail4.neteven.com ([127.0.0.1]) by localhost (mail4.neteven.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id E5RVs-zxLmze; Mon, 18 May 2015 16:21:26 +0200 (CEST) Message-ID: <5559F558.6050307@neteven.com> Date: Mon, 18 May 2015 16:21:12 +0200 From: Thomas SIMON User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: weishan.ang@gmail.com CC: "pgsql-admin@postgresql.org" Subject: Re: Performances issues with SSD volume ? References: <5559E3AD.7090109@neteven.com> <5559EABB.1060405@neteven.com> In-Reply-To: Content-Type: multipart/alternative; boundary="------------000901090007090205070309" X-Pg-Spam-Score: -1.9 (-) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-admin Precedence: bulk Sender: pgsql-admin-owner@postgresql.org This is a multi-part message in MIME format. --------------000901090007090205070309 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Wei, Yes i'm using RAID (megacli card), battery is ok, i had already checked BBU :) Cheers Thomas Le 18/05/2015 15:52, Wei Shan a écrit : > > Hi Thomas, > > This is just a wild guess. Are you using hardware RAID? Is the cache > battery still working? > > Cheers > > On 18 May 2015 9:36 pm, "Thomas SIMON" > wrote: > > Hi matheus, > thanks for reply. > > Kernel is slightly different ; with a 3.10.23-xxxx-std-ipv6-64 > kernel (OVH kernel) on HDD server, and 3.2.65-1+deb7u1 kernel on > SSD server. > I'm using debian wheezy on both servers. > > I didn't changed the 2 parameters you talk about. > > Thanks, > > Thomas > > Le 18/05/2015 15:13, Matheus de Oliveira a écrit : >> >> On Mon, May 18, 2015 at 10:05 AM, Thomas SIMON >> > wrote: >> >> After the change, I had the following behavior, and I don't >> understand why : everything seems to work fine (load is ~6/7, >> when it was previously ~25/30 on the HDD server), so the SSD >> server is faster than the HDD one, and my apps run faster >> too, but after some time (can be 5 minutes or 2 hours), the >> load average increases suddently (can reach 150 !) and does >> not decrease, so postgres and my application are almost >> unusable. (even small requests are in statement timeout) >> >> >> Before we go mad, what is the OS/kernel/distro that you are >> using? Did it change from the previous one? >> >> If Linux, have you disabled transparent_huge_pages and >> zone_reclaim_mode (two known problematic Linux features)? >> >> Best regards, >> -- >> Matheus de Oliveira >> Analista de Banco de Dados >> Dextra Sistemas - MPS.Br nível F! >> www.dextra.com.br/postgres >> > --------------000901090007090205070309 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit
Hi Wei,
Yes i'm using RAID (megacli card), battery is ok, i had already checked BBU :)

Cheers
Thomas
Le 18/05/2015 15:52, Wei Shan a écrit :

Hi Thomas,

This is just a wild guess. Are you using hardware RAID? Is the cache battery still working?

Cheers

On 18 May 2015 9:36 pm, "Thomas SIMON" <tsimon@neteven.com> wrote:
Hi matheus,
thanks for reply.

Kernel is slightly different ; with a 3.10.23-xxxx-std-ipv6-64 kernel (OVH kernel) on HDD server, and  3.2.65-1+deb7u1 kernel on SSD server.
I'm using debian wheezy on both servers.

I didn't changed the 2 parameters you talk about.

Thanks, 
Thomas
Le 18/05/2015 15:13, Matheus de Oliveira a écrit :

On Mon, May 18, 2015 at 10:05 AM, Thomas SIMON <tsimon@neteven.com> wrote:
After the change, I had the following behavior, and I don't understand why : everything seems to work fine (load is ~6/7, when it was previously ~25/30 on the HDD server), so the SSD server is faster than the HDD one, and my apps run faster too, but after some time (can be 5 minutes or 2 hours), the load average increases suddently (can reach 150 !) and does not decrease, so postgres and my application are almost unusable. (even small requests are in statement timeout)

Before we go mad, what is the OS/kernel/distro that you are using? Did it change from the previous one?

If Linux, have you disabled transparent_huge_pages and zone_reclaim_mode (two known problematic Linux features)?

Best regards,
--
Matheus de Oliveira
Analista de Banco de Dados
Dextra Sistemas - MPS.Br nível F!
www.dextra.com.br/postgres



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